Compression ignition engines rely on the heat of compression to ignite the air/fuel mixture (hereinafter "fuel mixture") in the engine cylinder. The expansion of the ignited fuel mixture drives the piston and thereby powers the engine. In cold weather, it is oftentimes difficult to generate sufficient heat through compression alone to ignite fuel mixture, especially since the cold engine block acts as a heat sink, removing heat from the fuel mixture as it is compressed. In some instances, some of the engine cylinders will fire while the others do not. If a cylinder does not fire the fuel mixture is expelled through the exhaust system in a vaporized form generically referred to as "white smoke."
Reducing white smoke emission is important for several reasons. For example, white smoke is a pollutant and reducing white smoke reduces that amount of pollutant released into the environment. Also, white smoke results in reduced fuel economy and performance.
Prior art engine control systems have recognized the undesirability of white smoke. To some extent, such systems have been developed to avoid generating white smoke during engine startup. However, each of those devices suffer from drawbacks. For example, a system directed toward reducing white smoke is shown in U.S. Pat. No. 4,928,642 issued to Atkinson on May 29, 1990. The Atkinson patent discloses a system for automatically injecting a starting fluid, during engine cranking and for a period of time after the engine starts, based on one or more engine parameters. Injecting the starting fluid during the starting period lowers the flash point of the air/fuel mixture in the engine combustion chamber, thereby causing the fuel to burn more completely and reduce the white smoke emissions.
Another example of a system directed toward reducing white smoke is U.S. Pat. No. 5,035,212 issued to Hudson on Jul. 30, 1991. The Hudson patent discloses an apparatus for an exhaust restrictor designed to reduce white smoke during low idle conditions, such as a marine boat trolling in low idle. The exhaust restrictor includes a valve connected to the exhaust system and the intake system. The valve includes a housing having a through passage to the exhaust system and the intake system. A shaft is rotatably positioned in the housing. A plate is attached to the shaft. The plate is positioned in the passage and is movable between an opened position and a closed position. A mechanical linkage is connected to the throttle and the shaft. The linkage will move the plate into a exhaust restricting position corresponding with the throttle being moved into a low idle position.
The system disclosed in the Atkinson patent and the Hudson patent both require the addition of a mechanical means, such as a starting fluid injector setup or a exhaust restrictor system including a plate mechanically linked with a throttle, to function. The addition of the mechanical means may increase the cost and complexity of the system.
An example of a method for electronically controlling the fuel injection rate and fuel injection duration is disclosed in U.S. Pat. No. 5,445,129 issued to Barnes on Aug. 29, 1995. The Barnes patent discloses, in part, a method for fuel to be injected in a series of very short bursts, which may provide for lower emissions and white smoke reduction. However, the Barnes patent does not disclose a cylinder cutout system dedicated to reducing white smoke.
It would be desirable to develop an apparatus and method for detecting engine operation that causes white smoke and changing engine operation to reduce white smoke output.